Doncricotopus Sæther

Description

Introduction

Small larvae.

Dorsal Head

Head capsule yellowish with dark postoccipital margin.

Antenna

Antenna with 5 segments; segments consecutively shorter until fifth, which is longer than fourth. Ring organ low on basal segment. Blade shorter than flagellum. Lauterborn organs distinct, longer than segment 3.

Labrum

All S setae described as simple but evidently SI can be apically finely divided apically into 2-3 fine branches. Labral lamellae absent. Pecten epipharyngis consisting of 3 long, smooth scales, with median scale slightly longer and broader. With 6 pairs of chaetulae laterales, long, simple; chaetulae basales weakly bifid at apex. Premandible with apical tooth; brush absent.

Mandible

Apical tooth longer than combined width of 4 inner teeth. Seta subdentalis slightly bent at apex. Seta interna with 6-7 smooth branches.

Mentum

Mentum with 2 median teeth and 6 pairs of lateral teeth; 2 first lateral teeth appressed toward median teeth. Ventromental plate broad, extending beyond margin of outer mental tooth; few but distinct setae (about 7) present in beard.

Maxilla

Pecten galearis with distinct base and weak, blunt teeth. Anterior lacinial chaeta broader than other lacinial chaetae.

Body

Body (based on larval exuviae). Parapods normally developed; medium-sized claws of anterior parapods with some strong, inner teeth. Procercus squat to higher than wide; posteriorly darkened with small but distinct medioposterior spur; with 5 anal setae. Anal tubules present. Body setae apparently short and simple.

Notes

Ecological Notes

At the time of the Holarctic key, the only known larva was reared from a stream or river in Northwest Territory, Canada (Sæther, 1981a). A second species is described from an adult from Finland (Tuiskunen, 1985a). The illustrated larva comes from Lake Superior in North America.

web design by Pawn Kong at skullisland.info